Processing of material and other mechanical operations related to mining are being automated to a greater extent in order to minimize costs. As a result, e.g. loaders have been developed, which follow automatically given commands and travel along a specific route to fetch broken rock from one place and unload the rock from the bucket to another place. In the prior art arrangement, the loader moves automatically between the locations and also empties the load from the bucket automatically, but during loading a remote operator controls the filling of the bucket via a telecommunications network since fully automatic loading of the bucket with the prior art methods is the prior art methods is not yet as efficient as manually controlled loading. When the loader moves, it should follow the predetermined route rather closely in order to remain within the allowed driving area and to be able to carry out the required operations correctly. The prior art teaches arrangements, based on dead reckoning and modelling and observation of the environment, for controlling the movement and determining the position of the machine.
The method of dead reckoning utilizes rotary movement of a component of the transmission equipment, typically the wheels, by measuring the distance travelled by the apparatus in proportion to the rotation of the wheels. The dead reckoning method also takes into account steering angles, i.e. either the steering angles of the turning wheels or the steering angle of the frame, so that the distance and direction of travel of the apparatus can also be calculated while the apparatus is turning. Although the obtained data is rather useful, it does contain some errors, wherefore the position of the apparatus must be checked in some other manner at suitable intervals. For this purpose the prior art teaches an arrangement where the surfaces surrounding the route along which the apparatus is moving, i.e. the shapes of the surfaces and the distance thereof from the intended route, are determined and stored in a memory by manually guiding the apparatus along a new route to be later driven automatically and by simultaneously determining the surfaces. The surface profile thus determined can be utilized in the determination of the exact position of the apparatus when it is moving automatically along the route. In this situation the actual calculation of the movement is based on the dead reckoning method in the prior art manners described above, which also includes observation of the surfaces surrounding the apparatus. The profile data from the determination of the surfaces is compared to the profile data stored in the memory, whereupon the longitudinal and transverse position of the apparatus with respect to the desired route can be determined accurately. Consequently, the corrective movements required to guide the apparatus back to the desired route can be performed automatically and the deviating position data obtained by the dead reckoning method can be corrected. Repeating the aforementioned measures at suitable, e.g. predetermined, intervals makes the loader move rather closely along a desired route. In addition to loaders, such an arrangement for guiding a machine along a specific route and for determining the position of the machine by means of the dead reckoning method and determination of the profiles of the surrounding wall surfaces can be used in connection be used in connection with other mining machines, such as haulage vehicles, drilling apparatuses, etc. For example in the present application and the claims, a mining machine refers to all possible machines and vehicles moving in a mine.
However, the aforementioned measuring method is not sufficiently accurate for loaders during loading, when the bucket is being filled with broken rock. To achieve maximum loading of the bucket, or a maximum transport capacity, it is not sufficient to merely drive the bucket into the pile of broken rock but the bucket must be guided and turned in various ways. Since the bucket must also be pushed into the pile of broken rock at a high speed, the wheels of the loader tend to skid and the loader may also deviate from the usual direction of travel during the filling of the bucket. In such a situation, the dead reckoning method is subjected to errors, which cause problems in the automatic control of the apparatus. Furthermore, at the training stage the environment of the loading site and particularly the direction of the material to be loaded may not have been observed and stored in full in the memory, since these matters usually change as the loading proceeds. Correspondingly, problems also occur in the determination of the position of other mining machines by means of the dead reckoning method when one or more of the vehicles' wheels skid with respect to the underlying surface, thus causing errors in the determination.